1. Field of the Invention
The present invention relates to a control panel for electronic equipment and a method of producing the same. More particularly, the present invention relates to a control panel for electronic equipment that is made of a synthetic resin material by injection molding. The present invention also relates to a method of producing the control panel for electronic equipment.
2. Discussion of Related Art
With the recent spread of equipment related to computers and communications equipment, it has been demanded that data input units, e.g. control panels, for entering information into such equipment and receiving information therefrom should be reduced in cost to an extreme. On the other hand, the achievement of high-precision electronic parts demands hermeticity for providing a dustproof structure and for preventing breakdown of electronic parts due to static electricity. For example, control panels used in electronic equipment, e.g. portable telephones and personal computers, are required to accomplish ultimate cost reductions in order to allow these electronic devices to spread at reduced costs. Switching structures including printed-circuit boards are particularly demanded to be reduced in cost.
The present applicant proposed a control panel for electronic equipment (see Japanese Patent Application Unexamined Publication (KOKAI) No. 9-259696). In the proposed control panel, basically, a button body that is touched with a finger is made of a synthetic resin material, and a printed indication is usually provided on the surface of the button body. However, because the indication is frequently touched with a finger, it may separate from the button body by friction. To solve this problems, various methods have been proposed. However, none of the proposed methods use a sheet. Therefore, if such a proposed method is adopted, the number of man-hours increases. If the proposed method is employed for a low-cost key sheet, the number of man-hours increases. Accordingly, the merit in adopting the proposed method reduces by half.
To meet the demands, the present applicant proposed a technique wherein pushbuttons and a control panel are assembled by injection molding (for example, see Japanese Patent No. 2649025). In the proposed technique, the clearance between each pushbutton and an opening in the control panel in which the pushbutton is disposed unavoidably becomes large because of the structure of the injection mold used for the injection molding process. From the viewpoint of the structure and design of electronic equipment and from the viewpoint of preventing entry of a foreign matter, it is desirable for the clearance to be as small as possible as long as the pushbutton can perform its function.
In view of the above-described technical background, the present invention attains the following objects.
An object of the present invention is to provide a control panel for electronic equipment in which the clearance between each opening in the control panel and a pushbutton placed in the opening is reduced, and also provide a method of producing the control panel for electronic equipment.
Another object of the present invention is to provide a control panel for electronic equipment that satisfies the requirements of hermeticity, clearness of indication and operability and yet allows a cost reduction, and also provide a method of producing the control panel for electronic equipment.
Still another object of the present invention is to provide a control panel for electronic equipment that is superior in mass-productivity and a method of producing the control panel for electronic equipment.
To attain the above-described objects, the present invention provides a control panel for operating electronic equipment that includes a control panel member and a pushbutton inserted in an opening formed in the control panel member. A pushbutton support supports the pushbutton with respect to the control panel member by elastically bending. A pushbutton collar is formed around the outer periphery of the pushbutton. The control panel member and the pushbutton collar have contact portions, respectively, at which the pushbutton collar and the control panel member come in close contact with each other, and when the pushbutton is operated, the pushbutton support elastically bends, causing the pushbutton collar and the control panel member to come out of contact with each other.
The contact portion of the control panel member may be a step formed on the rear side of the control panel member to block a flow of a molten resin material in an injection mold when the pushbutton support is injection-molded. The contact portions are kept in close contact with each other by the pressure applied during the injection molding process. Therefore, no gap is produced between the contact portions, and thus the flow of the resin material is effectively blocked.
The arrangement may be such that the pushbutton and the pushbutton support are not joined together into one unit. In this case, the pushbutton is preferably coated with a non-welding agent that prevents thermowelding of the pushbutton and the pushbutton support.
In addition, the present invention provides a first method of producing a control panel for electronic equipment. According to the first method, a sheet is formed to produce a plurality of recesses thereon by thermoforming. The recesses form pushbutton outer skins. The sheet formed with the recesses is inserted into an injection mold, and a molten resin material is filled into the recesses to form a key sheet. A control panel member for inserting the key sheet therein and the key sheet are inserted into an injection mold, and a molten synthetic resin material is injected into a cavity defined by the key sheet, the control panel member and the injection mold to fill the cavity with the molten synthetic resin material, thereby molding a pushbutton support.
As the sheet, a general-purpose sheet is preferable from the viewpoint of the cost, and a substantially transparent resin material is preferable. A synthetic resin material that welds to other synthetic resin materials is most suitable for use as the sheet.
In addition, the present invention provides a second method of producing a control panel for electronic equipment. According to the second method, a sheet is formed to produce a plurality of recesses thereon by thermoforming. The recesses form pushbutton outer skins. The sheet is cut into the pushbutton outer skins individually. A control panel member for inserting the pushbutton outer skins therein and the pushbutton outer skins are inserted into an injection mold, and a molten synthetic resin material is injected into a cavity defined by each of the pushbutton outer skins, the control panel member and the injection mold to fill the recess and the cavity with the molten synthetic resin material, thereby molding a pushbutton support.
In the first or second method of producing a control panel for electronic equipment according to the present invention, it is preferable that the control panel member and a pushbutton outer skin collar formed around the outer periphery of each of the pushbutton outer skins should have contact portions, respectively, at which the pushbutton outer skin collar and the surface of the control panel member contact each other to block a flow of the molten synthetic resin material.
In the first or second method of producing a control panel for electronic equipment according to the present invention, the sheet is preferably printed with an indication layer for each pushbutton before the step of thermoforming the sheet.
In addition, the present invention provides a third method of producing a control panel for electronic equipment. According to the third method, a plurality of pushbuttons connected to each other are molded, and the molded pushbuttons are cut off from each other. A control panel member and the pushbuttons are inserted into an injection mold, and a molten synthetic resin material is injected into a cavity defined by the pushbuttons, the control panel member and the injection mold to fill the cavity with the molten synthetic resin material, thereby molding a pushbutton support.
In the third method of producing a control panel for electronic equipment according to the present invention, it is preferable that the control panel member and a pushbutton collar formed around the outer periphery of each of the pushbuttons should have contact portions, respectively, at which the pushbutton collar and the surface of the control panel member contact each other to block a flow of the molten synthetic resin material. It is also preferable that the pushbuttons should be made of a transparent synthetic resin material, and that an indication layer for each of the pushbuttons should be printed on the rear side of the pushbutton in a state where the pushbuttons are connected together by runners molded when the pushbuttons are molded.
In the third method of producing a control panel for electronic equipment according to the present invention, the pushbuttons and the pushbutton support may not be joined together into one unit. In this case, the pushbuttons are preferably coated with a non-welding agent that prevents thermowelding of the pushbuttons and the pushbutton support during the injection molding process.
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings.